With the development of computer and network technology, it is a common sight nowadays that multiple applications co-exist on the same electronic equipment. For example, multiple applications co-exist on the same computer or multiple Web services are simultaneously provided on one Web server.
Every application needs to occupy resources in an electronic equipment, such as central processing unit (CPU) resources, memory resources and the like. However, the amount of resources needed by every application varies due to specific properties of every application, e.g. time complexity, space complexity and the like. Thus, an electronic equipment wherein a plurality of applications co-exist is often faced with a difficult problem of how to rationally adjust resources among all applications.
To guarantee normal running of every application even under extreme conditions, a usual practice is to provide a maximum of resources for every application. Obviously, such a practice will cause part of resources to leave idle during normal running, thereby a waste phenomenon.
Web service is a brand-new distributed computing environment, the basic idea of which is to utilize open standard technology to realize distributed software development, software engineering and software use on the Internet. Here, “service” refers to various software distributed on the Internet. Any user, whether he is an entity user or an individual user, can use Web service technology to schedule existing service software on the Internet and construct his own application software on the basis of service demands. Scheduling can be performed among application software of different entities and among application software of customers and entities via the Web service technology, so as to support e-business, customer relation model and other applications. Although the meaning of the Web service technology is completely different from that of common Web which is only capable of providing data service, the adopted protocols and interfaces belong to the Web technology which has already in common use. The basic technology of Web service is XML, which is defined by W3C. XML is an extensible markup language for the use of data description. Different from hypertext markup language (HTML), XML describes only data contents per se but does not touch upon data display, so it can be used to describe any generalized contents. In Web services, it is XML that is used to describe remote scheduling operation and its enforcement results. This description is loaded in the simple object access protocol (SOAP), and a SOAP message is usually transmitted in the most common HTTP. Since XML text description is irrelevant to enforcement, interactions can be conducted via Web services among platforms employing different operating systems and different programming languages. The release and description of Web services per se is also implemented using XML.
Service level agreements (SLA) are commonly used by Web service providers to define their contractual service obligations to their customers. These contractual service obligations usually include response time commitments. If the service obligations are not met, the customer might be entitled to be reduction in the fees owned to the Web service provider. Web service providers are therefore highly motivated to meet the commitments in their SLAs.
To meet the SLAs, the Web service providers often provide excess capacity when statically provisioning resources for their customers because it is hard to accurately predict demands, especially for the scenarios that some customers may occasionally experience a “web storm”, i.e. a dramatic temporary surge in demand. For example, a particular web service may experience a heavy request volume caused by an emergent event. The statically provisioned resources according to the average requirements can not deal with such a situation, which will cause the SLA violations. If excess capacity is provided in order to meet the SLAs under various sudden conditions, a great cost of resources is thus paid, which is unacceptable to the Web service provider.
Therefore, there is a need to dynamically adjust resources, i.e., to dynamically adjust resources allocated to each Web service according to requirements of each Web service on resources, so as to accomplish rational adjustment of resources.
Though existing electronic equipment can provide real-time reports on resource consumption, they are merely able to provide the total amount of resources consumed by the entire progress in a unit of progress or task. It is hard to provide resources consumed by each application respectively when multiple applications co-exist in one process or task. That is to say, the prior art is just able to obtain the amount of resources jointly consumed by several applications, but can not possess the proportion of resources consumed by each application in the process or task, i.e. resource consumption ratio. Therefore, in this case, existing electronic equipment cannot dynamically adjust resources among each application in one process or task on the basis of the prediction of resource consumption amount.
Besides, Grid technology which has developed lately allows enterprises to share resources as they form “virtual organizations”. That is, the enterprises, which may be geographically widespread locations and which may have heterogeneous computing platforms, share their resources and services to form virtual services. The open grid services architecture (OGSA) developed by academic and scientific communities, along with commercial entities (such as IBM) is an evolution of Grid technology. OGSA enables the grid to provide the enterprises with a set of extensible services collected by the virtual organizations.
The emerging Web service resource framework (WSRF) technology is also an evolution of Grid technology. All services on Grid will be Web services with WS-Resources if the business logics of the Web services have a certain state. Thus, in this disclosure, Grid services are called “Web services” to represent the service provisioned on Grid.
Compared to the normal computing noncommercial Grids that have sufficient resources available to satisfy all concurrent users, commercial grids profit by maintaining the smallest possible set of resources that can still meet user demand. To do so, such commercial grids must efficiently manage competing demands for the same resource set. Also, since the customers of commercial Grids pay for resources, they will not tolerate being denied service or being rescheduled to a different time slot, i.e., they will not tolerate the SLA violation. Thus, it is necessary that Web services providers dynamically provision on the nodes Web services provisioned on these grids according to the present resource consumption and demands. When the demands of one Web service increase to the peak which the present resources assigned can not meet, this Web service can be remote cloned to other available nodes in the commercial Grids to get additional resources. When the demands drop down, the Web service can be moved from the node to release the additional resource for other Web services. Thus, it is necessary to observe or monitor the resource consumption of Web services for management, especially SLA enforcement. While existing tools of Web services (for example, tools developed by AmberPoint Company) focus on the measurement of SLA/Quality of Service (QoS) such as performance and security that is not enough for the Web services dynamically provisioning based on commercial Grids. Firstly, the SLA measurement can not indicate the root cause of the SLA violation, so that correct remedial measures can not be taken. For example, Web service A is found to be with a delayed response time by the SLA measurement tool, and then it is decided to schedule more resources for Web service A; while the real reason causing the response time delay of Web service A may be that the resource required by Web service A has been consumed or exhausted by Web service B running on the same electronic equipment/server. Secondly, even the detected SLA violation can be used for dynamically provisioning of the Web service, the SLA has already been violated and the customer has experienced the degraded quality of service before supplying the gap by allocating additional resources.
Therefore, the resource consumption of Web services should be measured to support the dynamical adjusting of resources, i.e., to proactively determine when and which Web service should be dynamically provisioned (remote cloned or moved) in commercial grids.